1. Field
The exemplary embodiments relate to a method and apparatus for canceling a vocal signal from an audio signal, and more particularly, to a method and apparatus for canceling a vocal signal from an audio signal by using a frequency smoothing method so as to generate an accompaniment signal having improved sound quality.
2. Description of the Related Art
Due to technological development, users may enjoy music by using various acoustic devices. These acoustic devices provide various functions including not only reproducing music but also providing an audio signal from which a vocal signal is cancelled.
A method of subtracting a signal by using a difference between a left channel signal and a right channel signal is widely used as a method of canceling a vocal signal from an original sound. Such a method is used in that an audio signal may be divided into a vocal signal and an accompaniment signal by musical instruments, wherein the vocal signals included in two channels are similar to each other.
However, a common component of the two channels includes not only the vocal signal but also background music, that is, the accompaniment signal. Thus, if the vocal signal is cancelled by using a signal subtraction method between two channels, the accompaniment signal commonly included in the two channels is also cancelled, in addition to the vocal signal, so that the accompaniment signal is partially damaged.
FIG. 1 is a spectrogram of an accompaniment signal in which a vocal signal is cancelled from an original sound by using a method of subtracting a signal. In FIG. 1, a horizontal axis denotes time, a vertical axis denotes frequency by using the number of samples, and a difference in amplitude of energy according to a change in the axes denotes density. Referring to FIG. 1, a bright part denotes that there is energy and a dark part denotes that there is no energy. In FIG. 1, there are dark parts in various points of the spectrogram of the accompaniment signal which denote that there is no energy. These dark parts represent holes, and non-uniform holes cause distortion such as musical noise. There is a large number of frequency holes in the spectrogram of FIG. 1. Thus, a method and apparatus for removing these frequency holes are required.